The Arthurian legends, written up in the 12th and 13th centuries,
enjoyed extraordinary popularity throughout Medieval Western Europe.
Very naturally, the characters of the Arthurian cycles were given
arms by writers, and as early as the late 12th c. conscious efforts
are made toward consistency within a work. By the late 13th c.,
a stable set of about 30 arms can be said to exist: this is described
in Brault's work.

The development of this Arthurian heraldry slows in the 14th c. but
picks up again in the 15th c. In France, in particular, a number of
armories of the knights of the Round Table were compiled from 1440 on.
Pastoureau has found 74 such armories in various libraries. They were
mainly intended as reference books for book illustrators in Paris and
Northern France as they painted illuminations for editions of the
Lancelot and Tristan stories. They all seem to come from the same source,
likely composed in the early 15th c. in Normandy.

The resulting armory published by Pastoureau contains 178 names, with
each a blazon, crest, supporters and a motto in French, Latin or Britton.
Nine out of ten characters are present in one of the major 13th c.
Arthurian works (Lancelot en prose, Tristan en prose, Guiron le Courtois).
Some important figures are missing: women but also some first-order
figures (Marc, Merlin, Uterpendragon, etc).

I only present a selection from Pastoureau's armory, with some of his
annotations.

In Meliador, an Arthurian romance by Jean Froissart (c1337-c1410), there are
a total of 43 coats of arms attributed to knights named and unnamed: they are described in an
appendix to the edition of the romance by Arthur Longnon, Paris, 1899.

Son of Urien. His motto alludes to Morguain,
his mother in a number of texts. In 13th c. texts he bears
Or a lion gules. The change in tinctures may be an enhancement,
due to the higher prestige of the azure/or combination (France, Arthur).